function DropLoad() {
	this.dropLoadSign = true;
	this.init();
}

DropLoad.prototype = {
	init: function() {

	},
	dropLoad: function(selection, callback) {
		var _this = this;
		$(window).scroll(function() {
			var ws = $(window).scrollTop();
			var ds = $(document).scrollTop();
			var h = $(window).height();
			var scrollTop = ws || ds;
			if(_this.getTop($(selection)) + $(selection).outerHeight() < h + scrollTop) {
				if(_this.dropLoadSign) {
					_this.dropLoadSign = false;
					callback();
				}
			}
		});
	},
	getTop: function(obj) {
		var iTop = 0;
		while(obj) {
			iTop += obj.offset().top;
			obj = obj.offsetParent();
			break;
		}
		return iTop;
	}
}